ACL graft with extra-cortical fixation rotates around the femoral tunnel aperture during knee flexion

2021 ◽  
Author(s):  
Junjun Zhu ◽  
Brandon Marshall ◽  
Xin Tang ◽  
Monica A. Linde ◽  
Freddie H. Fu ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Femoral Tunnel ◽  
Acl Graft

scholarly journals The effect of femoral tunnel placement on ACL graft orientation and length during in vivo knee flexion

2011 ◽  
Vol 44 (10) ◽  
pp. 1914-1920 ◽  
Author(s):  
Ermias S. Abebe ◽  
Jong-Pil Kim ◽  
Gangadhar M. Utturkar ◽  
Dean C. Taylor ◽  
Charles E. Spritzer ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Femoral Tunnel ◽  
Tunnel Placement ◽  
Acl Graft ◽  
Femoral Tunnel Placement

scholarly journals Creating a Femoral Tunnel Aperture at the Anteromedial Footprint Versus the Central Footprint in ACL Reconstruction: Comparison of Contact Stress Patterns

2021 ◽  
Vol 9 (4) ◽  
pp. 232596712110018
Author(s):  
Sung-Jae Kim ◽  
Si Young Song ◽  
Tae Soung Kim ◽  
Yoon Sang Kim ◽  
Seong-Wook Jang ◽  
...  
Keyword(s):  
Acl Reconstruction ◽  
Contact Stress ◽  
Femoral Tunnel ◽  
Single Bundle ◽  
Central Group ◽  
Acl Graft ◽  
Anterior Aspect ◽  
Extended Position ◽  
The Difference ◽  
Stress Patterns

Background: It remains unclear whether an anteromedial (AM) footprint or a central footprint anterior cruciate ligament (ACL) graft exhibits less contact stress with the femoral tunnel aperture. This contact stress can generate graft attrition forces, which can lead to potential graft failure. Purpose/Hypothesis: The purpose of this study was to compare the difference in contact stress patterns of the graft around a femoral tunnel that is created at the anatomic AM footprint versus the central footprint. It was hypothesized that the difference in femoral tunnel positions would influence the contact stress at the interface between the reconstructed graft and the femoral tunnel orifice. Study Design: Controlled laboratory study. Methods: A total of 24 patients who underwent anatomic single-bundle ACL reconstruction were included in this study. In 12 patients, the femoral tunnels were created at the center of the native AM footprint (AM group), and in the remaining 12 patients the center of the femoral tunnel was placed in the anatomic central footprint (central group). Three-dimensional knee models were created and manipulated using several modeling programs, and the graft-tunnel angle (GTA) was determined using a special software program. The peak contact stresses generated on the virtual ACL graft around the femoral tunnel orifice were calculated using a finite element method. Results: The mean GTA was significantly more obtuse in the AM group than in the central group (124.2° ± 5.9° vs 112.6° ± 7.9°; P = .001). In general, both groups showed high stress distribution on the anterior surface of the graft, which came in contact with the anterior aspect of the femoral tunnel aperture. The degree of stress in the central group (5.3 ± 2.6 MPa) was significantly higher than that in the AM group (1.2 ± 1.1 MPa) ( P < .001). Conclusion: Compared with the AM footprint ACL graft, the central footprint ACL graft developed significantly higher contact stress in the extended position, especially around the anterior aspect of the femoral tunnel orifice. Clinical Relevance: The contact stress of the ACL graft at the extended position of the knee may be minimized by creating the femoral tunnel at the AM-oriented footprint.

scholarly journals The Relationship Between Lateral Femoral Anatomic Structures and the Femoral Tunnel Outlet in Anterior Cruciate Ligament Reconstruction Using the Transportal Technique: A 3-Dimensional Simulation Analysis

2020 ◽  
Vol 8 (9) ◽  
pp. 232596712095278
Author(s):  
Kwangho Chung ◽  
Chong Hyuk Choi ◽  
Sung-Hwan Kim ◽  
Sung-Jae Kim ◽  
Woosung Do ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Femoral Tunnel ◽  
Cruciate Ligament ◽  
Lateral Collateral Ligament ◽  
Tunnel Length ◽  
Tunnel Wall ◽  
Lateral Epicondyle ◽  
3 Dimensional ◽  
Anterior Cruciate ◽  
The Relationship

Background: The relationship between the lateral femoral anatomic structures and femoral tunnel outlet according to changes in knee flexion and transverse drill angle during femoral tunnel creation in anterior cruciate ligament (ACL) reconstruction remains unclear. Purpose: To investigate the relationships between the lateral femoral anatomic structures and femoral tunnel outlet according to various knee flexion and transverse drill angles and to determine appropriate angles at which to minimize possible damage to the lateral femoral anatomic structures. Study Design: Controlled laboratory study. Methods: Simulation of ACL reconstruction was conducted using a 3-dimensional reconstructed knee model from the knees of 30 patients. Femoral tunnels were created using combinations of 4 knee flexion and 3 transverse drill angles. Distances between the femoral tunnel outlet and lateral femoral anatomic structures (minimum safe distance, 12 mm), tunnel length, and tunnel wall breakage were assessed. Results: Knee flexion and transverse drill angles independently affected distances between the femoral tunnel outlet and lateral femoral anatomic structures. As knee flexion angle increased, the distance to the lateral collateral ligament, lateral epicondyle, and popliteal tendon decreased, whereas the distance to the lateral head of the gastrocnemius increased ( P < .001). As the transverse drill angle decreased, distances to all lateral femoral anatomic structures increased ( P < .001). Considering safe distance, 120°, 130°, or 140° of knee flexion and maximum transverse drill angle (MTA) could damage the lateral collateral ligament; 130° or 140° of knee flexion and MTA could damage the lateral epicondyle; and 110° or 120° of knee flexion and MTA could damage the lateral head of the gastrocnemius. Tunnel wall breakage occurred under the conditions of MTA – 10° or MTA – 20° with 110° of knee flexion and MTA – 20° with 120° of knee flexion. Conclusion: Approximately 120° of knee flexion with MTA – 10° and 130° or 140° of knee flexion with MTA – 20° or MTA – 10° could be recommended to prevent damage to the lateral femoral anatomic structures, secure adequate tunnel length, and avoid tunnel wall breakage. Clinical Relevance: Knee flexion angle and transverse drill angle may affect femoral tunnel creation, but thorough studies are lacking. Our findings may help surgeons obtain a stable femoral tunnel while preventing damage to the lateral femoral anatomic structures.

A Preclinical Model to Study the Influence of Graft Force on the Healing of the Anterior Cruciate Ligament Graft

2018 ◽  
Vol 32 (05) ◽  
pp. 441-447
Author(s):  
Richard Ma ◽  
Mark Stasiak ◽  
Xiang-Hua Deng ◽  
Scott Rodeo
Keyword(s):  
Anterior Cruciate Ligament ◽  
Acl Reconstruction ◽  
Knee Flexion ◽  
Cruciate Ligament ◽  
Tunnel Position ◽  
Anterior Cruciate Ligament Graft ◽  
Acl Graft ◽  
Anterior Cruciate ◽  
Femoral Graft

AbstractThe purpose of this study is to establish a small animal anterior cruciate ligament (ACL) reconstruction research model where ACL graft force can be varied to create different graft force patterns with controlled knee motion. Cadaveric (n = 10) and in vivo (n = 10) rat knees underwent ACL resection followed by reconstruction using a soft tissue autograft. Five cadaveric and five in vivo knees received a nonisometric, high-force femoral graft tunnel position. Five cadaveric and five in vivo knees received a more isometric, low-force graft tunnel position. ACL graft force (N) was then recorded as the knee was ranged from extension to 90 degrees using a custom knee flexion device. Our results demonstrate that distinct ACL graft force patterns were generated for the high-force and low-force femoral graft tunnels. For high-force ACL grafts, ACL graft forces increased as the knee was flexed both in cadaveric and in vivo knees. At 90 degrees of knee flexion, high-force ACL grafts had significantly greater mean graft force when compared with baseline (cadaver: 7.76 ± 0.54 N at 90 degrees vs. 4.94 ± 0.14 N at 0 degree, p = 0.004; in vivo: 7.29 ± 0.42 N at 90 degrees vs. 4.74 ± 0.13 N at 0 degree, p = 0.007). In contrast, the graft forces for low-force ACL grafts did not change with knee flexion (cadaver: 4.94 ± 0.11 N at 90 degrees vs. 4.72 ± 0.14 N at 0 degree, p = 0.41; in vivo: 4.78 ± 0.26 N at 90 degrees vs. 4.77 ± 0.06 N at 0 degree, p = 1). Compared with nonisometric ACL grafts, the graft force for grafts placed in an isometric position had significantly lower ACL graft forces at 15, 30, 45, 60, 70, and 90 degrees in both cadaveric and in vivo knees. In conclusion, we have developed a novel ACL reconstruction model that can reproducibly produce two ACL graft force patterns. This model would permit further research on how ACL graft forces may affect subsequent graft healing, maturation, and function.

Comparison of Anterior Cruciate Ligament Graft Isometry between Paired Femoral and Tibial Tunnels

2017 ◽  
Vol 30 (09) ◽  
pp. 960-964 ◽  
Author(s):  
E. Cain ◽  
Marcus Biggers ◽  
Benton Emblom ◽  
Jeffrey Dugas ◽  
David Beason
Keyword(s):  
Anterior Cruciate Ligament ◽  
Range Of Motion ◽  
Femoral Tunnel ◽  
Cruciate Ligament ◽  
Tibial Tunnel ◽  
Tunnel Placement ◽  
Posterior Aspect ◽  
Acl Graft ◽  
Posterior Tibial ◽  
Anterior Cruciate

AbstractAccurate tunnel placement is important for a successful anterior cruciate ligament (ACL) reconstruction. Controversy exists concerning the preferred method of femoral tunnel preparation, with proponents of both medial portal and transtibial drilling techniques. Current ACL literature suggests that placement of the femoral ACL attachment site posterior or “low” in the ACL footprint leads to more anatomically correct ACL mechanics and better rotational control. There is limited literature focusing on ACL graft displacement through knee range of motion based on specific paired placement of femoral and tibial tunnels. Our purpose was to assess ACL isometry between multiple combinations of femoral and tibial tunnels. We hypothesized that placement of the graft at the posterior aspect of the ACL footprint on the femur would be significantly less isometric and lead to more graft displacement as compared with central or anterior placement. The ACL of matched pairs of cadaveric knees was arthroscopically debrided while leaving the soft tissue footprint on the femur and tibia intact. One knee from each pair underwent notchplasty. In all knees, three femoral and three tibial tunnels were created at the anterior, central, and posterior aspects of the ACL footprint. A suture was passed through each tunnel combination (nine potential pairs), and the change in isometry was measured throughout full knee range of motion. Placement of the femoral tunnel along the posterior aspect of the ACL footprint was less isometric compared with a central or anterior position in the femoral footprint. Placement of a posterior tibial tunnel also led to decreased isometry, but tibial tunnel placement affected isometry to a lesser extent than femoral tunnel placement. The combination of a posterior femoral and posterior tibial tunnel resulted in greater than 1 cm of graft excursion from full flexion to extension. Placement of ACL tunnels at anisometric sites may adversely affect the mechanical properties and behavior of the ACL graft, resulting in either graft laxity in flexion or overconstraint and loss of extension.

scholarly journals No Difference in Ligamentous Strain or Knee Kinematics Between Rectangular or Cylindrical Femoral Tunnels During Anatomic ACL Reconstruction With a Bone–Patellar Tendon–Bone Graft

2021 ◽  
Vol 9 (6) ◽  
pp. 232596712110095
Author(s):  
Timothy A. Burkhart ◽  
Takashi Hoshino ◽  
Lachlan M. Batty ◽  
Alexandra Blokker ◽  
Philip P. Roessler ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Acl Reconstruction ◽  
Patellar Tendon ◽  
Knee Flexion ◽  
Femoral Tunnel ◽  
Knee Kinematics ◽  
Anatomic Acl Reconstruction ◽  
Anterior Translation ◽  
Ligament Strain ◽  
Bone Patellar Tendon

Background: As our understanding of anterior cruciate ligament (ACL) anatomy has evolved, surgical techniques to better replicate the native anatomy have been developed. It has been proposed that the introduction of a rectangular socket ACL reconstruction to replace a ribbon-shaped ACL has the potential to improve knee kinematics after ACL reconstruction. Purpose: To compare a rectangular femoral tunnel (RFT) with a cylindrical femoral tunnel (CFT) in terms of replicating native ACL strain and knee kinematics in a time-zero biomechanical anatomic ACL reconstruction model using a bone–patellar tendon–bone (BTB) graft. Study Design: Controlled laboratory study. Methods: In total, 16 fresh-frozen, human cadaveric knees were tested in a 5 degrees of freedom, computed tomography–compatible joint motion simulator. Knees were tested with the ACL intact before randomization to RFT or CFT ACL reconstruction using a BTB graft. An anterior translation load and an internal rotation moment were each applied at 0°, 30°, 60°, and 90° of knee flexion. A simulated pivot shift was performed at 0° and 30° of knee flexion. Ligament strain and knee kinematics were assessed using computed tomography facilitated by insertion of zirconium dioxide beads placed within the substance of the native ACL and BTB grafts. Results: For the ACL-intact state, there were no differences between groups in terms of ACL strain or knee kinematics. After ACL reconstruction, there were no differences in ACL graft strain when comparing the RFT and CFT groups. At 60° of knee flexion with anterior translation load, there was significantly reduced strain in the reconstructed state ([mean ±standard deviation] CFT native, 2.82 ± 3.54 vs CFT reconstructed, 0.95 ± 2.69; RFT native, 2.77 ± 1.71 vs RFT reconstructed, 1.40 ± 1.76) independent of the femoral tunnel type. In terms of knee kinematics, there were no differences when comparing the RFT and CFT groups. Both reconstructive techniques were mostly effective in restoring native knee kinematics and ligament strain patterns as compared with the native ACL. Conclusion: In the time-zero biomechanical environment, similar graft strains and knee kinematics were achieved using RFT and CFT BTB ACL reconstructions. Both techniques appeared to be equally effective in restoring kinematics associated with the native ACL state. Clinical Relevance: These data suggest that in terms of knee kinematics and graft strain, there is no benefit in performing the more technically challenging RFT as compared with a CFT BTB ACL reconstruction.

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